Mounting means for electromagnetic armature



Sept. 16, 1969 A. J. KRALIK MOUNTING MEANS FOR ELECTROMAGNETIC ARMATURE 3 Sheets-Sheet 1 Filed Dec. 12. 1966 Sept- 16, 1969 A. J. KRALIK 3,467,924

MOUNTING MEANS FOR ELECTROMAGNETIC ARMATURE Filed Deo. 12, 1966 n 3 Sheets-Sheet 3 United States Patent C 3,467,924 f MOUNTING MEANS FOR ELECTROMAGNETIC ARMATURE Andrew J. Kralik, Detroit, Mich., assignor, by mesne assignments, to I-T-E Imperial Corporation, Philadelphia, Pa., a corporation of Delaware Filed Dec. 12, 1966, Ser. No. 601,020 Int. Cl. H01h 50/18, 51/06, 9/54 U.S. Cl. 335-203 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to electromagnetic contactors 1n general and more particularly relates to contactors of this type having novel resilient means for controlling `armature pole face attitude during the closing stroke.

In the Cataldo et al. copending application Ser. No. 189,915, filed Apr 24, 1962, now Patent No. 3,324,431, entitled Electrical Device, and assigned to the assignee of the intan-t invention, there is disclosed an electromagnetic contactor structure in which the armature is mounted for linear movement toward the stationary yoke when the magnet coil is energized. With the magnet deenergized a biasing means urges the armature against an abutment of the movable Contact carrier shaped to constitute a pivot about which the armature is free to move for self alignment of its pole faces with the mating pole faces of the yoke when the magnet is in sealed condition. It has been found that because the pole faces are not parallel as they initially engage, extensive use of such type contactors, especially in the larger size range, results in peening of the pole face edges and corners. As this condition progresses magnet holding force decreases and noise of operation increases.

In order -to eliminate this undesirable condition the instant invention provides novel means for maintaining the mating pole faces parallel during the closing stroke without impeding armature freedom of movement for self alignment of the mating pole faces when in the sealed condition.

More particularly, l`this invention provides a biasing means, which, when the magnet is deenergized, moves the armature away from its pivot abutment and into engagement with another abutment Of the movable contact carrier. The latter abutment is so positioned that the armature and yoke pole faces are parallel. With the magnet deenergized, this armature biasing means exerts a greater force than the magnet return springs which urge the movable contact carrier away from the magnet yoke. Thus, during the entire closing stroke the armature remains engaged with the latter abutment and the mating pole faces remain parallel thereby preventing peening of the pole face edges and corners.

Accordingly, a primary object of the instant invention is to provide a novel construction for an electromagnet to increase efficient operating life thereof.

Another object is to provide an electromagnet with an armature operated for linear movement and having novel means for maintaining the armature and yoke pole faces parallel during the entire closing stroke.

Still another object is to provide an electromagnetic contactor with a linearly movable armature and means ICC biasing the armature with respect to the movable contact carrier in a direction away from the yoke.

A further object is to provide an electromagnetic contactor in which a linearly movable armature is connected to the movable contact carrier in such a manner that the armature and yoke pole faces remain parallel during the entire closing stroke and the mating pole faces are free for self alignment when in the sealed condition.

These as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIGURE l is a perspective of an electromagnetic contactor having an armature mounted in accordance with the teachings of the instant invention.

FIGURE 2 is a perspective principally illustrating the movable and stationary contac-t carriers.

FIGURE 3 is a side elevation illustrating the armature mounted to the movable contact carrier.

FIGURE 4 is a view similar to FIGURE 3 with portions of the armature and movable contact carrier cut away to more clearly illustrate the interconnection of these elements.

FIGURE 5 is an exploded perspective of the elements of FIGURES 3 and 4.

FIGURES 6 and 7 are schematics illustrating the mode of opera-tion for the contactor. In FIGURE 6 the magnet coil is deenergized while in FIGURE 7 the coil iS energized and the armature pole faces sealed to the yoke pole faces.

Now referring to the figures. Electromagnetic contactor 10 is of the type illustrated for the most part in the aforesaid copending application Ser. No. 189,915. Holding interlock 11 mounted at the left of contactor 10 is mechanically and electrically coordinated therewith in a manner described in detail in the aforesaid copending application Ser. No. 189,915, now Patent No. 3,324,431.

Briefly, contactor 10 includes molded base 12 wherein coil assembly 13 and stationary yoke 14 are mounted. Return springs 16, 16 bias movable contact carrier 17 away from yoke 14. Bridging contacts 18a, 18h, 18e mounted on upward or forward projections of movable contact carrier 17 cooperate with pairs of spaced stationary contacts 19a, 19h, 19C, respectively, mounted to stationary contact carrier 21. With these cooperating contacts closed, contact pressure springs 31a, 31b, 31e are subject to increased loading. It is noted that even though the schematics of FIGURES 6 and 7 illustrate springs 31a, 31h, 31C as being tension members, in the physical embodiment these springs are coiled compression members.

Each of the return springs 16, 16 are coiled compression members mounted to a different post 23 which guides movable contact carrier 17 for linear movement toward and away from yoke 14. Removable cover 22 encloses the sets of cooperating contacts 18a-19a, 18b-19b, 18e-19C.

Movable contact carrier 17 includes molded portion 17a and sheet metal portion 17b secured together by rivets 26. Member 17b is provided with tail piece 17C which, as described in detail in the aforesaid copending application Ser. No. 189,915, assists in guiding movement of movable contact carrier 17.

In addition to stationary yoke 14 the flux path or magnetic frame includes movable armature 15. Armature 15' is a C-shaped member having outer legs 15a, 15b connected by middle leg 15C. Outer legs 15a, 15b straddle main portion 17d of carrier member 17b. Coiled compression spring 25 interposed between carrier member 17b and the lower surface of middle leg 15C biases armature 15 upward against insulating sheet 27 interposed between middle leg 1Sc and molded carrier portion 17a.

3 As seen in the schematics of FIGURES 6 and 7, the lower end of spring 25 surrounds upward protrusion 17e of member 17b while the upper end of spring 25 is received in annular groove d in the lower surface of the armature middle leg 15C.

With coil means 13 deenergized as in FIGURE 6 air gaps 31,V 32 in magnetic frame 14, 15 are of maximum length separating pole faces 15a, 15b of armature 15 from pole faces 14a, 14b of yoke 14. The molded part 17a of contact carrier 17 is so constructed that the surface thereof against which middle leg 15C abuts (with insulating sheet 27 interposed therebetween) maintains the pole faces at the lower ends of armature legs 15a, 15b parallel -to their respective confronting pole faces at the upper ends of yoke legs 14a, 14b.

With coil means 13 energized, magnetic flux force attracts armature 15 to yoke 14. The relative forces of armature spring 25, return springs 16, 16 and contact presssure springs 31a, 31b, 31c are such that the upper surface of armature leg 15C remains in abu-tment with the molded part 17a of contact carrier 17 until initial engagement of the cooperating contacts 18a-19a, 18b- 19b, 18e-19e. Continued movement of armature 15 toward yoke 14 vincreases the loading on return spring 16 and contact pressure springs 31a, 31h, 31C so that the combined force exerted thereby exceeds the force exerted by armature spring 25. Thus, armature spring compresses permitting the lower surface of armature middle leg 15C to engage abutment 17e of carrier part 17b. Aburtment 17e is spherical providing a universal pivot for armature 15 whereby the latter is free to move and permit self alignment of the pole faces of armature legs 15a, 15b with the pole faces of yoke legs 14a, 14b in the sealed condition of FIGURE 7.

Thus, it is seen that the instant invention provides novel means to maintain parallelism between armature and yoke pole faces during the closing stroke of an electromagnet.

Although there has been described a preferred embodiment of this novel invention, many variations and modiiications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

What I claim is:

1. In an electromagnetic device including an elec-tromagnet comprising an operating coil and a magnetic frame with a relatively stationary yoke and a relatively movable armature, means mounting said armature for movement toward said yoke upon energization of said coil, a carrier to which said armature is movably mounted, and first biasing means urging said carrier away from said yoke, wherein the improvement comprises second biasing means mounted to said carrier and urging said armature away from said yoke, with said coil deenergized said second biasing means effective to operate said armature against an abutment of said carrier, said first and said second biasing means being proportioned so that with said coil energized magnetic forces move said armature away from said abutment against forces generated by said second biasing means.

2. A device as set forth in claim 1 also including normally open cooperating contact means connected to said carrier whereby movement of said armature toward said yoke is effective to close said contact means, third biasing means acting on said contact means when closed to provide contact pressure therefor, when said contact means is closed forces derived from said second and said third biasing means acting on said carrier in opposite directions, loading of said lirst biasing means increasing as said carrier moves toward said yoke, said first and said second biasing means being proportioned so that upon energization of said coil said armature remains in engagement with said abutment at least until closing of said contact means.

3. A device as set forth in claim 2 in which loading of said third biasing means increases upon energization of said coil after initial closing of said contaot means.

4. A device as set forth in claim 3 in which the armature upon moving away from said abutment moves toward and into engagement with another abutment of said carrier.

5. A device as set forth in claim 4 in which said another abutment constitutes a pivot for said armature to compensate for misalignment between confronting pole face means of said armature and said yoke.

6. A device as set forth in claim 5 in which the pole face means of said armature are substantially parallel to said abutment when said coil is deenergized.

7. A device as set forth in claim 6 in which said armature is a C-shaped member having outer legs conneoted by a middle leg, said second biasing means comprising compression spring means acting between said carrier and the middle leg.

8. A device as set forth in claim 7 in which said spring means acts on one side of said leg and the other side of said leg engages the abutment.

9. A device as set forth in claim 8 in which said one side of said leg engages said another abutment.

References Cited UNITED STATES PATENTS 2,908,784 10/1959 Kuhn 335-131 3,076,075 1/ 1963 Colvill 335-126 3,205,324 9/1965 Drie'sch S35-270 3,324,270 6/ 1967 Lacan.

BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner 

